Most, if not all aspects of female mammalian reproductive physiology are subject to partial or complete control by neural or hormonal influences; however, interrelationships between peripheral nerves, the endocrines and reproductive function are poorly understood. Recent studies in our laboratory using the rat and guinea pig have demonstrated the following: (1) Abdominal vagotomy inhibits the FSH and LH rise at 5 and 24 hours normally seen following unilateral ovariectomy. (2) Abdominal vagotomy during pregnancy results in increased fetal resorption and decreased serum levels of LH and progesterone, and decreased ovarian progesterone. (3) Cutting the pelvic parasympathetic nerves (pelvic neurectomy (PN)) in rats on days 8-10 of pregnancy blocks parturition. PN rats fail to show the characteristic progesterone drop on day 22, the expected day of parturition, however, by day 23 or 24, progesterone is down but the fetuses are still retained in utero. With this background, we propose to further investigate the roles of the vagus nerve and pelvic parasympathetic nerves in reproductive function. Peripheral blood levels and pituitary content of FSH and LH and serum progesterone will be evaluated in pregnant vagotomized rats. Also, pregnant vagotomized rats will be given LH, LH and prolactin or LHRF in an attempt to overcome the interruption of pregnancy characteristic of vagotomized animals. The endocrine profile (UOV blood analyzed for oxytocin, estradiol, prostaglandin F2 alpha and 20 alpha-dihydroprogesterone, ovaries analyzed for 20 alpha hydroxysteroid dehydrogenase) of PN animals will be characterized in the parturient period in an attempt to determine the mechanism by which PN blocks parturition. The fine structure of the uterine myometrium will be examined for the presence of gap junctions since the formation of these membranous contacts is believed to be necessary for parturition. Lastly, oxytocin will be infused in PN animals at term in an attempt to induce parturition. Collectively, these studies will provide insight on the role of the peripheral nervous system in reproductive function.